Project description:Histone modifcations and CTCF binding at the c-myb locus were compared in cell lines with c-myb expressing, which are myeloblatic M1 cells and leukemia cells with virus integration, VS. M1 cells without c-myb expression induced by IL-6. Distribution of active histone marks at the c-myb gene and the upstream regions are associated with active c-myb transcription. The enrichment of all of these active histone marks decreased with differentiation-induced down-regulation of c-myb, but increased and spread in tumor cells. ChIP-on-chip from murine myeloid cell line M1 and virus-induced myeloid leukemia cell lines for H3K4me3, H3K9/14ac, H3K4me1, H3K27me3, H3K9me3 and CTCF
Project description:Histone modifcations and CTCF binding at the c-myb locus were compared in cell lines with c-myb expressing, which are myeloblatic M1 cells and leukemia cells with virus integration, VS. M1 cells without c-myb expression induced by IL-6. Distribution of active histone marks at the c-myb gene and the upstream regions are associated with active c-myb transcription. The enrichment of all of these active histone marks decreased with differentiation-induced down-regulation of c-myb, but increased and spread in tumor cells.
Project description:The transcription factor c-Myb a key regulator in proliferation and differentiation of hematopoietic progenitor cells, is precisely regulated during essential cellular processes. Overexpression and rearrangement of c-myb has been reported in human tumors including myeloid leukemia, but exact regulatory mechanisms have remained elusive. Here, we identified, using 4C assay with the c-myb promoter as an anchor, the interaction site at -34k region upstream of c-myb gene that are involved in c-myb expression. Furthermore, we found that the long-range interactions changed with c-myb being down-regulated on differentiation progress in human myeloid leukemia cell lines. Taken together, our date revealed that a potential c-myb enhancer-promoter interactions may be a particularly important regulatory mechanism for c-myb gene expression in human myeloid leukemia cells.
Project description:The B-myb (MYBL2) gene is a member of the MYB family of transcription factors and is involved in cell cycle regulation, DNA replication and maintenance of genomic integrity. However, its function during adult development and hematopoiesis is unknown. We show here that conditional inactivation of B-myb in vivo results in depletion of the HSC pool, leading to profound reductions in mature lymphoid, erythroid and myeloid cells. This defect is autonomous to the bone marrow and is first evident in the HSCs, which accumulate in the S and G2/M phases. B-myb inactivation also causes defects in the myeloid progenitor compartment and results in an accumulation of GMPs. Microarray studies indicate that B-myb null LKS+ cells differentially express genes that direct myeloid lineage development and commitment, suggesting that B-myb is a key player in controlling cell fate. Collectively, these studies demonstrate that B-myb is essential for HSC and progenitor maintenance and survival during hematopoiesis. Total RNA was isolated from FACS purified LKS+ cells isolated from pIpC-treated control and B-myb floxed-MxCre mice. Each sample is derived from a pool of 3-5 mice. 2 samples were analyzed for each genotype.
Project description:Differentiation of hemopoietic stem cells into granulocytes is characterized by distinct changes in the transcriptome. We analyzed mRNA expression in primary murine myeloid cells at four successive stages of hemopoietic differentiation; Lin- Sca1+ cKit+ stem/progenitor cells (LSKs), promyelocytes, myelocytes and granulocytes. Using fluorescence–activated cell sorting, we isolated primary murine myeloid cells at four successive stages of hemopoietic differentiation; Lin- Sca1+ cKit+ stem/progenitor cells (LSK), promyelocytes, myelocytes and granulocytes.
Project description:We report genome-wide pattern of Myb chromatin occupancy in vivo. We used ERMYB, a myeloid progenitor cell line derived by transformation of primary cells by ER-Myb fusion protein, as our model system. In these cells, activation of the ER-Myb fusion protein by estrogen is required to maintain a proliferative progenitor-like phenotype. We performed ChIP-seq with biological duplicate samples from ERMYB cells with Myb either “on” or “off” (i.e. + or - ?-E2 for 6 hr). By comparing enrichment signals between Myb-on, Myb-off and isotype control samples, we identified 7,646 high-confidence Myb binding regions, which can be assigned to 4,892 annotated genes according to their distances to the nearest transcriptional start sites. Examination of Myb chromatin occupany in myeloid cells transformed by a switchable form of Myb
